Manipulating superconductivity in ruthenates through Fermi surface engineering

TL;DR

This paper proposes a combined theoretical and experimental approach to manipulate superconductivity in ruthenates by strain-induced Fermi surface engineering, predicting optimal conditions for triplet pairing enhancement.

Contribution

It introduces a novel strategy integrating weak-coupling renormalization group theory with strain engineering to control superconductivity in ruthenates.

Findings

Qualitatively reproduces recent uniaxial strain experiments.

Shows strain can bring Fermi surface close to van Hove singularity.

Predicts maximum T_c for triplet pairing near, but not on, the singularity.

Abstract

The key challenge in superconductivity research is to go beyond the historical mode of discovery-driven research. We put forth a new strategy, which is to combine theoretical developments in the weak-coupling renormalization group approach with the experimental developments in lattice strain driven Fermi surface-engineering. For concreteness we theoretically investigate how superconducting tendencies will be affected by strain engineering of ruthenates' Fermi surface. We first demonstrate that our approach qualitatively reproduces recent experiments under uniaxial strain. We then note that order few $\%$ strain readily accessible to epitaxial thin films, can bring the Fermi surface close to van Hove singularity. Using the experimental observation of the change in the Fermi surface under biaxial epitaxial strain and ab-initio calculations, we predict ${\rm T}_{\rm c}$ for triplet pairing to be maximized by getting close to the van Hove singularities without tuning on to the singularity.